A more effective and efficient maintenance paradigm is emerging that replaces time-based maintenance with a condition-based maintenance approach. This approach allows equipment to be operated for more of its useful life and significantly reduces the cost of maintaining equipment. In order to implement this maintenance plan, there is a need for more sensitive and reliable sensors for monitoring the state of equipment.

In the case of bearings and other rotating devices, accelerometers and thermocouples are being replaced by more sensitive microelectromechanical systems (MEMS). MEMS sensors have the ability to detect faults in rotating machinery early enough to effectively administer condition-based maintenance; however, current MEMS sensors require batteries, which have short life spans and reliability issues, or wires that add weight when many sensors are used and require routine servicing to ensure effective operation.

Researchers at Purdue University have developed an integrated, wireless, battery-free MEMS sensing device for monitoring the internal state of a bearing or other rotating machine. In addition, the MEMS sensor is installed inside the rotating machine. This is advantageous where add-ons to existing components are often not implemented due to the additional cost and logistical support.